The present disclosure relates to a gate driver circuit.
In general, a gate driver circuit of a power switch element generates and provides an appropriate gate voltage (e.g., 20V) to drive a gate of such a power switch element by using an input signal having a low voltage (e.g., 5V or less).
In addition, when a fault is generated, for example, in the case that a current flowing in the power switch element becomes an over-current, power in the driver circuit is abnormal, or the like, the power switch element needs to be turned off by blocking a gate driving signal.
In this case, the power switch element needs to be softly turned off, for example, slowly turned off. This is so as not to damage the power switch element or peripheral circuits when such a fault is generated.
In addition, in the case that a power switch element such as an insulated gate bipolar transistor (IGBT), a metal-oxide semiconductor field-effect-transistor (MOSFET), or the like is turned off, a malfunction may occur, in which the power switch element is turned on again, because of an increase in a gate voltage due to Miller capacitance between a collector and a base (parasitic capacitance formed between a collector and a gate) when a collector voltage is sharply increased. In order to prevent such a malfunction, a clamp circuit is required.
Typically, in a switch circuit configured of a high side power switch element and a low side power switch element, in order to drive the low side power switch element, a semiconductor element used in an integrated circuit needs to have a breakdown voltage of 20V or more.
In this case, as a semiconductor process technology is developed, a line width of a level of 0.35 μm or less may be used even in a process for a semiconductor element having a breakdown voltage of 20V or more, but in the case that such a semiconductor element has a large breakdown voltage, an area thereof may be increased.
Characteristics of this process may be that a logic circuit portion may be designed and manufactured by using a low voltage (5V or less) element, and a circuit driving a power element may be designed and manufactured by using a medium voltage (20V level or more) element. When the integrated circuit is implemented, since an area of the low voltage element is significantly smaller than that of such a medium voltage element, the logic circuit implemented using such a low voltage element alone may allow an area of the integrated circuit to be very small, as compared to the logic circuit and the driver circuit implemented using only the medium element. Therefore, there is a need for research into and development of a logic circuit using such a low voltage element.
A gate driver circuit of a power switch element according to the related art includes a gate driver circuit for driving a gate voltage of the IGBT and a logic circuit for detecting a voltage of a gate driving signal. In general, since such a logic circuit directly receives a gate driving signal, such a logic circuit may be destroyed.
For example, in the case in which a gate voltage is received through an inverter to allow the gate voltage of the IGBT element to be sensed, since the gate voltage may be generally increased up to 20V, the inverter may be destroyed in the case in which the element having an input gate breakdown voltage smaller than 20V is used.
Therefore, in a gate driver circuit capable of performing a soft turn-off operation or agate clamp operation, performed when a fault is generated, in order to use the logic circuit to detect the gate signal, there is a need for research into and development of a gate driver circuit capable of detecting a high gate voltage.